1. Field of the Invention
The present invention relates to a curing apparatus, system, and method. More particularly, the present invention relates to a solid state light device, system, and method that may replace current high intensity directed light sources and techniques that are used for curing applications.
2. Background Art
Illumination systems are used in a variety of applications. Home, medical, dental, and industrial applications often require light to be made available. Similarly, aircraft, marine, and automotive applications often require high-intensity illumination beams.
Traditional lighting systems have used electrically powered filament or arc lamps, which sometimes include focusing lenses and/or reflective surfaces to direct the produced illumination into a beam. Conventional light sources based on powered filament or arc lamps, such as incandescent or discharge bulbs, radiate both heat and light in 360 degrees. Conventional sources also include microwave-driven sources. Thus, for traditional applications, the optics used must be designed and/or specially treated to withstand the constant heating effects caused by the high intensity (and high heat) discharge bulbs. In addition, expensive and complicated heat transfer systems must be employed if heat is to be removed from the area of illumination.
For example, conventional curing systems utilize water chill rolls to minimize distortion and/or destruction of the substrate and/or the formulation. Other conventional systems utilize a flat water chill plate located just below or in contact with the substrate.
For curing applications, stacked-LED arrays are now being investigated (e.g., arrays that can be “stacked” in a cross-machine-direction (CMD) and machine-direction (MD) manner). With these conventional systems, however, the irradiance and lifetime drop quickly as the LED emission wavelengths get shorter. This may lead to problems with initiating chemical reactions via radiation absorption and response by photoinitiators, which are typically formulated to absorb radiation less than 450 nm. If the irradiance is too low, it is possible that the polymerization reaction would not yield desired product properties.
To counteract low irradiance, a conventional technique is to position LEDs close to one another to increase the overall irradiance and attain desired cure. However, arranging the LEDs in such a manner results in several complications relating to thermal management and electrical connections. If the LEDs are more spread out, irradiance uniformity across the array can become non-ideal. Reflectors are sometimes mounted around the LEDs to improve irradiance levels, but this approach still suffers from non-uniformity across the reflector opening. If an appropriate material is not used within the reflector, the irradiance will also drop by the square of the distance to the irradiated surface.